Actin cytoskeleton plays crucial roles in various cellular functions.Extracellular matrix(ECM)can modulate cell morphology by remodeling the internal cytoskeleton.To define how geometry of ECM regulates the organizati...Actin cytoskeleton plays crucial roles in various cellular functions.Extracellular matrix(ECM)can modulate cell morphology by remodeling the internal cytoskeleton.To define how geometry of ECM regulates the organization of actin cytoskeleton,we plated individual NIH 3T3 cells on micropatterned substrates with distinct shapes and sizes.It was found that the stress fibers could form along the nonadhesive edges of T-shaped pattern,but were absent from the opening edge of V-shaped pattern,indicating that the organization of actin cytoskeleton was dependent on the mechanical environment.Furthermore,a secondary actin ring was observed on 50μm circular pattern while did not appear on 30μm and 40μm pattern,showing a size-dependent organization of actin cytoskeleton.Finally,osteoblasts,MDCK and A549 cells exhibited distinct organization of actin cytoskeleton on T-shaped pattern,suggesting a cell-type specificity in arrangement of actin cytoskeleton.Together,our findings brought novel insight into the organization of actin cytoskeleton on micropatterned environments.展开更多
Formate can be synthesized electrochemically by CO_(2) reduction reaction(CO_(2)RR)or formalde-hyde oxidation reaction(FOR).The CO_(2)RR approach suffers from kinetic-sluggish oxygen evolution reac-tion at the anode.T...Formate can be synthesized electrochemically by CO_(2) reduction reaction(CO_(2)RR)or formalde-hyde oxidation reaction(FOR).The CO_(2)RR approach suffers from kinetic-sluggish oxygen evolution reac-tion at the anode.To this end,an electrochemical sys-tem combining cathodic CO_(2)RR with anodic FOR was developed,which enables the formate electrosynthesis at ultra-low voltage.Cathodic CO_(2)RR employing the BiOCl electrode in H-cell exhibited formate Faradaic efficiency(FE)higher than 90% within a wide potential range from−0.48 to−1.32 V_(RHE).In flow cell,the current density of 100 mA cm^(−2) was achieved at−0.67 V_(RHE).The anodic FOR using the Cu_(2)O electrode displayed a low onset potential of−0.13 V_(RHE) and nearly 100%formate and H_(2) selectivity from 0.05 to 0.35 V_(RHE).The CO_(2)RR and FOR were constructed in a flow cell through membrane electrode assembly for the electrosynthesis of formate,where the CO_(2)RR//FOR delivered an enhanced current density of 100 mA cm^(−2) at 0.86 V.This work provides a promising pair-electrosynthesis of value-added chemicals with high FE and low energy consumption.展开更多
Periwinkle Littoraria sinensis is a widely distributed gastropod in rocky intertidal zone of the northwestern Pacifi c.To examine genetic diversity and genetic connectivity among coastal populations of L.sinensis in C...Periwinkle Littoraria sinensis is a widely distributed gastropod in rocky intertidal zone of the northwestern Pacifi c.To examine genetic diversity and genetic connectivity among coastal populations of L.sinensis in China,1636 pairs of primers were successfully designed using whole-genome shotgun sequencing,de novo assembly,and a bioinformatics pipeline QDD.Twelve highly variable polymorphic markers were selected to genotype 351 individuals from 15 populations.Data of nine microsatellite loci were retained for population genetic analysis,and weak genetic differentiation among populations were detected,suggesting high gene flow among populations.The long planktonic larval duration of L.sinensis might have played an important role in the high gene flow among populations.A tendency of genetic differentiation between north and south populations of L.sinensis was detected,which might be resulted from isolation due to lowered sea level in the last glacial maximum.Furthermore,the newly founded populations along the coast of Jiangsu Province were closely related to populations to the south of the Changjiang(Yangtze)River estuary,suggesting that the main source of the newly founded populations is from natural rocky populations south of the estuary.展开更多
The quality and safety of agricultural products are closely related to human health.They also play an important role in enhancing the competitiveness of China’s agricultural products market,shaping the brand value of...The quality and safety of agricultural products are closely related to human health.They also play an important role in enhancing the competitiveness of China’s agricultural products market,shaping the brand value of agricultural products,and promoting the high-quality development of agriculture.At present,there are still a series of problems in the quality and safety of agricultural products.Relevant departments of the state should strengthen guidance and supervision,improve the quality and safety awareness and management level of agricultural product producers,and encourage producers to participate in the product certification and process certification of agricultural products.In addition,it is necessary to take effective control measures in accordance with the certification requirements,to evaluate their effectiveness,so as to improve the quality and safety of agricultural products and promote the high-quality development of China’s agriculture.展开更多
Geometric error is the main factor affecting the machining accuracy of hybrid machine tools.Kinematic calibration is an effective way to improve the geometric accuracy of hybrid machine tools.The necessity to measure ...Geometric error is the main factor affecting the machining accuracy of hybrid machine tools.Kinematic calibration is an effective way to improve the geometric accuracy of hybrid machine tools.The necessity to measure both position and orientation at each pose,as well as the instability of identification in case of incomplete measurements,severely affects the application of traditional calibration methods.In this study,a kinematic calibration method with high measurement efficiency and robust identification is proposed to improve the kinematic accuracy of a five-axis hybrid machine tool.First,the configuration is introduced,and an error model is derived.Further,by investigating the mechanism error characteristics,a measurement scheme that only requires tool centre point position error measurement and one alignment operation is proposed.Subsequently,by analysing the effects of unmeasured degrees of freedom(DOFs)on other DOFs,an improved nonlinear least squares method based on virtual measurement values is proposed to achieve stable parameter identification in case of incomplete measurement,without introducing additional parameters.Finally,the proposed calibration method is verified through simulations and experiments.The proposed method can efficiently accomplish the kinematic calibration of the hybrid machine tool.The accuracy of the hybrid machine tool is significantly improved after calibration,satisfying actual aerospace machining requirements.展开更多
Glycosyl imidates are among the pioneering donors for catalytic glycosylation.We report a new generation of imidates featuring the presence of a pentafluorophenyl group,introduced via substitution on imidoyl fluoride ...Glycosyl imidates are among the pioneering donors for catalytic glycosylation.We report a new generation of imidates featuring the presence of a pentafluorophenyl group,introduced via substitution on imidoyl fluoride which is easily prepared,stable and user-friendly.The resulting donors exhibit exceptional shelf stability while can be readily activated to achieve high-yielding glycosylation,encompassing comprehensively aldosyl,ketosyl and ulosonyl donors,and both O-and N-glycosylation acceptors.Notably,the reactivity gradient across different generations of imidates,coupled with the accessible imidate acceptor from selective reaction of imidoyl fluoride at the anomeric hydroxyl group,enables a fully catalytic one-pot synthesis of oligosaccharides.展开更多
Reversible boronate-catechol linkage was widely used to construct two-dimensional coatings and threedimensional nanostructures or hydrogels.The construction of these functional materials usually requires the pre-synth...Reversible boronate-catechol linkage was widely used to construct two-dimensional coatings and threedimensional nanostructures or hydrogels.The construction of these functional materials usually requires the pre-synthesis of macro molecular building blocks,and direct gelation between natural polyphenols and small molecule boranic acids is yet to be investigated.In this study,we fabricated a family of allsmall-molecule dynamic covalent gels consisting of tannic acid and boronic acids.Transparent and thixotropic gels were formed by boronate affinity towards catechol groups abundant on natural polyphenols.The gels showed multi-responsiveness,such as acid-,base-,reduction-and oxidantsensitive depending on the used boronic acid building blocks.The chemistry for gel formation and stimuli-responsiveness was characterized by11B NMR spectroscopy.The multi-stimuli responsiveness,green processing and facile modular design make the boronic acid-tannic acid gels promising candidates for the development of smart soft materials.展开更多
The Arabidopsis b HLH010/089/091(basic helix-loop-helix)genes are functionally redundant and are required for both anther development and normal expression of DYT1-activated anther-related genes.These three genes are ...The Arabidopsis b HLH010/089/091(basic helix-loop-helix)genes are functionally redundant and are required for both anther development and normal expression of DYT1-activated anther-related genes.These three genes are conserved in Brassicaceae,suggesting that each of them is under selection pressure;however,little is known about the possible functional differences among these b HLH genes and between the b HLH and DYT1 genes.Here,we compared novel anther transcriptomic data sets from b HLH010/089/091 single and double mutants,with an anther transcriptomic data set from the wild type(WT)and a previously obtained anther transcriptomic data set from the bhlh010 bhlh089 bhlh091 triple mutant.The results revealed molecular phenotypes that support the functional redundancy and divergence of b HLH010,b HLH089,and b HLH091,as well as the functional overlap and difference between them and DYT1.DNA-binding analyses revealed that DYT1 and b HLH089 specifically recognize the TCATGTGC box to activate the expression of target genes,including ATA20,EXL4,and MEE48.In addition,among genes whose expression was affected in the bhlh010 bhlh089 double and bhlh010 bhlh089 bhlh091 triple mutants,genes that are involved in the stress response and cell signaling were enriched,which included256 genes whose expression was preferentially induced by heat during early flower development.Moreover,the bhlh double mutants exhibited defective pollen development when the plants were grown under elevated temperature,suggesting that b HLH genes are important for anther gene expression under such conditions.These results are consistent with the observation that the heat-induced expression of several genes is less in the bhlh mutants than that in the WT.Therefore,our results provide important insights into the molecular mechanism underlying the activation of direct targets by DYT1-b HLH089 heterodimers and demonstrate the protective roles of b HLH010/089/091 in maintaining fertility upon heat stress.展开更多
Better understanding of electrochemical reaction behaviors of hydrazine electrooxidation at metal phosphides has long been desired and the optimization of reaction kinetics has been proved to be operable.Herein,the de...Better understanding of electrochemical reaction behaviors of hydrazine electrooxidation at metal phosphides has long been desired and the optimization of reaction kinetics has been proved to be operable.Herein,the dehydrogenation kinetics of hydrazine electrooxidation at Ni_(2)P is adjusted by Co as the(Ni_(0.6)Co_(0.4))_(2)P catalyzes HzOR effectively with onset potential of–45 mV and only 113 mV is needed to drive the current density of 50 mA cm^(‒2),showing over 60 mV lower than Ni_(2)P and Co_(2)P.It also delivers the maximum power density of 263.0 mW cm^(-2) for direct hydrazine fuel cell.Detailed experimental results revealed that Co doping not only decreases the adsorption energy of N_(2)H_(4) on Ni sites,lowering the energy barrier for dehydrogenation,but also acts as the active sites in the optimal reaction coordination to boost the reaction kinetics.This work represents a breakthrough in improving the catalytic performance of non‐precious metal electrocatalysts for hydrazine electrooxidation and highlights an energy‐saving electrochemical hydrogen production method.展开更多
High entropy oxides(HEOs) have attracted extensive attention of researchers due to their remarkable properties. The electrocatalytic activity of electrocatalysts is closely related to the reactivity of their surface a...High entropy oxides(HEOs) have attracted extensive attention of researchers due to their remarkable properties. The electrocatalytic activity of electrocatalysts is closely related to the reactivity of their surface atoms which usually shows a positive correlation. Excellenet stability of HEOs leads to their surface atoms with relative poor reactivity, limiting the applications for electrocatalysis. Therefore, it is significant to activate surface atoms of HEOs. Constructing amorphous structure, introducing oxygen defects and leaching are very effective strategies to improve the reactivity of surface atoms. Herein, to remove chemical inert, low-crystallinity(Fe, Co, Ni, Mn, Zn)_(3)O_(4) (HEO-Origin) nanosheets with abundant oxygen vacancies was synthesized, showing an excellent catalytic activity with an overpotential of 265 mV at 10 mA/cm^(2), which outperforms as-synthesized HEO-500℃-air(335 mV). The excellent catalytic performance of HEO-Origin can be attributed to high activity surface atoms, the introduction of oxygen defects efficiently altered electron distribution on the surface of HEO-Origin. Apart from, HEO-Origin also exhibits an outstanding electrochemical stability for oxygen evolution reaction(OER).展开更多
Numerous polysaccharides isolated from plants have been used to augment traditional drugs in the treatment of cancer.In order to explore the influence to hepatocellular carcinoma,a novel cold water-soluble polysacchar...Numerous polysaccharides isolated from plants have been used to augment traditional drugs in the treatment of cancer.In order to explore the influence to hepatocellular carcinoma,a novel cold water-soluble polysaccharide was separated from Rhodiola rosea L.root(RLP)and then its structure and anti-cancer activities were tested.The chemical compositions and high performance gel permeation chromatography(HPGPC)results indicated that RLP was an acid heteropolysaccharide with the molecular weight of about1.15×10~6 Da.Furthermore,ion chromatography(IC),Fourier transform infrared(FT-IR)and nuclear magnetic resoance(NMR)further indicated that RLP was main composed of→2,4)-α-Rha(1→,→5)-α-L-Araf-(1→,α-D-Glu,→6)-β-D-Galp-(1→,β-D-Man and→4)-α-GalpA-(1→.In vivo antitumor activities of RLP were carried out by using H22 tumor-bearing mice model.The results shown that RLP(100 and 300 mg/kg)could inhibit tumor growth of H22 cells from 23.59%to 45.52%and protect thymuses and spleen without damage.In addition,according to cell cycle,AV-FITC/PI and JC-1,RLP could induce dose-dependent apopto sis of H22 cells via S phase arrested which was through a mitochondrial related pathway.Our data indicated that RLP has a broader application prospect in anti-tumor preparations.展开更多
UAV-aided energy-harvesting WBANs where sensor nodes can harvest RF energy transmitted by a UAV have attracted considerable attention.However,how to maximize the sum-throughput of the sensor nodes with crosstier inter...UAV-aided energy-harvesting WBANs where sensor nodes can harvest RF energy transmitted by a UAV have attracted considerable attention.However,how to maximize the sum-throughput of the sensor nodes with crosstier interferences from satellite and cellular systems has not been addressed.In order to bridge this gap,we devote this paper to developing two schemes with the fixed or variable duration of the energy-harvesting phase.Specifically,we formulate two non-convex optimization problems corresponding to the two schemes,and transform them to tractable subproblems,and accordingly two algorithms are proposed named HA-PC-TA and UAVPC-TA.In particular,we derive the closed-form optimum transmit power and time allocation for the sensor nodes and obtain the optimum UAV's hovering altitude in HA-PC-TA.We reveal the relationship between the optimum parameters and the allowed maximum transmit power of the VAU in UAVPC-TA.Finally,the simulations are conducted to validate the effectiveness of our proposed solutions.展开更多
Background:This study aimed to develop and validate test-based physical literacy scales(PLSs)for primary school students across different grades.Methods:Data were collected through a field survey conducted from June 1...Background:This study aimed to develop and validate test-based physical literacy scales(PLSs)for primary school students across different grades.Methods:Data were collected through a field survey conducted from June 1 to July 31,2022,involving 3,275 primary school students from four provinces in China.The questionnaires assessed four domains:physical knowledge,physical competence,physical motivation,and physical behavior.The Rasch model was employed for psychometric analysis.Results:The variance explained by measures for the PLSs was 53.1%,50.3%,and 54.7%,all exceeding the 50%threshold,confirming unidimensionality and robust internal consistency.This enabled effective differentiation among students with varying proficiency levels.The item-person map demonstrated optimal alignment between item difficulty and participant ability levels.Most items showed favorable fit statistics,with Infit mean square(MNSQ)and Outfit MNSQ values ranging between 0.5 and 1.5.Conclusions:The PLSs demonstrate validity and reliability in measuring physical literacy among Chinese primary school students across four components:physical knowledge,physical competence,physical motivation,and physical behavior.The scales measure a unidimensional construct,supporting the use of summed total scores for assessment.展开更多
Current gold standard for the replacement of small-diameter blood vessel(ID<4 mm)is still to utilize the autologous vessels of patients due to the limitations of small-diameter vascular grafts(SDVG)on weak endothel...Current gold standard for the replacement of small-diameter blood vessel(ID<4 mm)is still to utilize the autologous vessels of patients due to the limitations of small-diameter vascular grafts(SDVG)on weak endothelialization,intimal hyperplasia and low patency.Herein,we create the SDVG with the tailored endothelialization by applying the engineered endothelial cell vesicles to camouflaging vascular grafts for the enhancement of vascular remodeling.The engineered endothelial cell vesicles were modified with azide groups(ECVs-N3)through metabolic glycoengineering to precisely link the vascular graft made of PCL-DBCO via click chemistry,and thus fabricating ECVG(ECVs-N3 modified SDVG),which assists inhibition of platelet adhesion and activation,promotion of ECs adhesion and enhancement of anti-inflammation.Furthermore,In vivo single-cell transcriptome analysis revealed that the proportion of ECs in the cell composition of ECVG surpassed that of PCL,and the tailored endothelialization enabled to convert endothelial cells(ECs)into some specific ECs clusters.One of the specific cluster,Endo_C5 cluster,was only detected in ECVG.Consequently,our study integrates the engineered membrane vesicles of ECVs-N3 from native ECs for tailored endothelialization on SDVG by circumventing the limitations of living cells,and paves a new way to construct the alternative endothelialization in vessel remodeling following injury.展开更多
Spontaneous nucleation of SiC particles and giant macroscopic steps result in the surface roughness of the grown crystal for the top-seeded solution growth of SiC crystal.To suppress the surface roughness,the temperat...Spontaneous nucleation of SiC particles and giant macroscopic steps result in the surface roughness of the grown crystal for the top-seeded solution growth of SiC crystal.To suppress the surface roughness,the temperature gradient was carefully adjusted by changing the relative position of the crucible and induction coils.The numerical simulation and experimental results show that the surface morphology of the grown crystal becomes smoother and there are fewer spontaneous nucleation particles attached to the growth surface with the decrease in the relative crucible position,due to the increase of temperature at the entire solution surface and the reducing of temperature gradient near the growth surface.Accordingly,a lower temperature gradient,a larger solution velocity,a higher carbon concentration,and a smaller carbon supersaturation near the growth surface can be obtained when the relative position between the crucible and the induction coil is 70 mm,which is demonstrated to be the most favorable for the elimination of spontaneous nucleation of small SiC particles and suppressing surface roughening with the full width at half maximum(FWHM)of 37.5 arcsec of 4Hsingle bondSiC crystals.展开更多
基金This work was supported by the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030009)the National Key Research and Development Program of China(2022YFC3400600)National Natural Science Foundation of China(12174208,32227802,11874231,31801134 and 31870843)+2 种基金Tianjin Natural Science Foundation(20JCYBJC01010)China Postdoctoral Science Foundation(2020M680032)Fundamental Research Funds for the Central Universities(2122021337 and 2122021405).
文摘Actin cytoskeleton plays crucial roles in various cellular functions.Extracellular matrix(ECM)can modulate cell morphology by remodeling the internal cytoskeleton.To define how geometry of ECM regulates the organization of actin cytoskeleton,we plated individual NIH 3T3 cells on micropatterned substrates with distinct shapes and sizes.It was found that the stress fibers could form along the nonadhesive edges of T-shaped pattern,but were absent from the opening edge of V-shaped pattern,indicating that the organization of actin cytoskeleton was dependent on the mechanical environment.Furthermore,a secondary actin ring was observed on 50μm circular pattern while did not appear on 30μm and 40μm pattern,showing a size-dependent organization of actin cytoskeleton.Finally,osteoblasts,MDCK and A549 cells exhibited distinct organization of actin cytoskeleton on T-shaped pattern,suggesting a cell-type specificity in arrangement of actin cytoskeleton.Together,our findings brought novel insight into the organization of actin cytoskeleton on micropatterned environments.
基金This work was supported by the National Key R&D Program of China(2020YFA0710000)the National Natural Science Foundation of China(22122901,21902047)+1 种基金the Provincial Natural Science Foundation of Hunan(2020JJ5045,2021JJ20024,2021RC3054)the Shenzhen Science and Technology Program(JCYJ20210324140610028).
文摘Formate can be synthesized electrochemically by CO_(2) reduction reaction(CO_(2)RR)or formalde-hyde oxidation reaction(FOR).The CO_(2)RR approach suffers from kinetic-sluggish oxygen evolution reac-tion at the anode.To this end,an electrochemical sys-tem combining cathodic CO_(2)RR with anodic FOR was developed,which enables the formate electrosynthesis at ultra-low voltage.Cathodic CO_(2)RR employing the BiOCl electrode in H-cell exhibited formate Faradaic efficiency(FE)higher than 90% within a wide potential range from−0.48 to−1.32 V_(RHE).In flow cell,the current density of 100 mA cm^(−2) was achieved at−0.67 V_(RHE).The anodic FOR using the Cu_(2)O electrode displayed a low onset potential of−0.13 V_(RHE) and nearly 100%formate and H_(2) selectivity from 0.05 to 0.35 V_(RHE).The CO_(2)RR and FOR were constructed in a flow cell through membrane electrode assembly for the electrosynthesis of formate,where the CO_(2)RR//FOR delivered an enhanced current density of 100 mA cm^(−2) at 0.86 V.This work provides a promising pair-electrosynthesis of value-added chemicals with high FE and low energy consumption.
基金Supported by the National Natural Science Foundation of China(No.31970488)。
文摘Periwinkle Littoraria sinensis is a widely distributed gastropod in rocky intertidal zone of the northwestern Pacifi c.To examine genetic diversity and genetic connectivity among coastal populations of L.sinensis in China,1636 pairs of primers were successfully designed using whole-genome shotgun sequencing,de novo assembly,and a bioinformatics pipeline QDD.Twelve highly variable polymorphic markers were selected to genotype 351 individuals from 15 populations.Data of nine microsatellite loci were retained for population genetic analysis,and weak genetic differentiation among populations were detected,suggesting high gene flow among populations.The long planktonic larval duration of L.sinensis might have played an important role in the high gene flow among populations.A tendency of genetic differentiation between north and south populations of L.sinensis was detected,which might be resulted from isolation due to lowered sea level in the last glacial maximum.Furthermore,the newly founded populations along the coast of Jiangsu Province were closely related to populations to the south of the Changjiang(Yangtze)River estuary,suggesting that the main source of the newly founded populations is from natural rocky populations south of the estuary.
文摘The quality and safety of agricultural products are closely related to human health.They also play an important role in enhancing the competitiveness of China’s agricultural products market,shaping the brand value of agricultural products,and promoting the high-quality development of agriculture.At present,there are still a series of problems in the quality and safety of agricultural products.Relevant departments of the state should strengthen guidance and supervision,improve the quality and safety awareness and management level of agricultural product producers,and encourage producers to participate in the product certification and process certification of agricultural products.In addition,it is necessary to take effective control measures in accordance with the certification requirements,to evaluate their effectiveness,so as to improve the quality and safety of agricultural products and promote the high-quality development of China’s agriculture.
基金supported by the National Natural Science Foundation of China(Nos.52275442 and 51975319)。
文摘Geometric error is the main factor affecting the machining accuracy of hybrid machine tools.Kinematic calibration is an effective way to improve the geometric accuracy of hybrid machine tools.The necessity to measure both position and orientation at each pose,as well as the instability of identification in case of incomplete measurements,severely affects the application of traditional calibration methods.In this study,a kinematic calibration method with high measurement efficiency and robust identification is proposed to improve the kinematic accuracy of a five-axis hybrid machine tool.First,the configuration is introduced,and an error model is derived.Further,by investigating the mechanism error characteristics,a measurement scheme that only requires tool centre point position error measurement and one alignment operation is proposed.Subsequently,by analysing the effects of unmeasured degrees of freedom(DOFs)on other DOFs,an improved nonlinear least squares method based on virtual measurement values is proposed to achieve stable parameter identification in case of incomplete measurement,without introducing additional parameters.Finally,the proposed calibration method is verified through simulations and experiments.The proposed method can efficiently accomplish the kinematic calibration of the hybrid machine tool.The accuracy of the hybrid machine tool is significantly improved after calibration,satisfying actual aerospace machining requirements.
基金the National Natural Science Foundation of China(No.21672147)Shanghai University of Traditional Chinese Medicine for financial support。
文摘Glycosyl imidates are among the pioneering donors for catalytic glycosylation.We report a new generation of imidates featuring the presence of a pentafluorophenyl group,introduced via substitution on imidoyl fluoride which is easily prepared,stable and user-friendly.The resulting donors exhibit exceptional shelf stability while can be readily activated to achieve high-yielding glycosylation,encompassing comprehensively aldosyl,ketosyl and ulosonyl donors,and both O-and N-glycosylation acceptors.Notably,the reactivity gradient across different generations of imidates,coupled with the accessible imidate acceptor from selective reaction of imidoyl fluoride at the anomeric hydroxyl group,enables a fully catalytic one-pot synthesis of oligosaccharides.
基金supported by the National Natural Science Foundation of China(No.21725402)the Shanghai Municipal Science and Technology Commission(No.17XD1401600)。
文摘Reversible boronate-catechol linkage was widely used to construct two-dimensional coatings and threedimensional nanostructures or hydrogels.The construction of these functional materials usually requires the pre-synthesis of macro molecular building blocks,and direct gelation between natural polyphenols and small molecule boranic acids is yet to be investigated.In this study,we fabricated a family of allsmall-molecule dynamic covalent gels consisting of tannic acid and boronic acids.Transparent and thixotropic gels were formed by boronate affinity towards catechol groups abundant on natural polyphenols.The gels showed multi-responsiveness,such as acid-,base-,reduction-and oxidantsensitive depending on the used boronic acid building blocks.The chemistry for gel formation and stimuli-responsiveness was characterized by11B NMR spectroscopy.The multi-stimuli responsiveness,green processing and facile modular design make the boronic acid-tannic acid gels promising candidates for the development of smart soft materials.
基金financially supported by grants from the National Natural Science Foundation of China(31822005,31670316,and 31870294)
文摘The Arabidopsis b HLH010/089/091(basic helix-loop-helix)genes are functionally redundant and are required for both anther development and normal expression of DYT1-activated anther-related genes.These three genes are conserved in Brassicaceae,suggesting that each of them is under selection pressure;however,little is known about the possible functional differences among these b HLH genes and between the b HLH and DYT1 genes.Here,we compared novel anther transcriptomic data sets from b HLH010/089/091 single and double mutants,with an anther transcriptomic data set from the wild type(WT)and a previously obtained anther transcriptomic data set from the bhlh010 bhlh089 bhlh091 triple mutant.The results revealed molecular phenotypes that support the functional redundancy and divergence of b HLH010,b HLH089,and b HLH091,as well as the functional overlap and difference between them and DYT1.DNA-binding analyses revealed that DYT1 and b HLH089 specifically recognize the TCATGTGC box to activate the expression of target genes,including ATA20,EXL4,and MEE48.In addition,among genes whose expression was affected in the bhlh010 bhlh089 double and bhlh010 bhlh089 bhlh091 triple mutants,genes that are involved in the stress response and cell signaling were enriched,which included256 genes whose expression was preferentially induced by heat during early flower development.Moreover,the bhlh double mutants exhibited defective pollen development when the plants were grown under elevated temperature,suggesting that b HLH genes are important for anther gene expression under such conditions.These results are consistent with the observation that the heat-induced expression of several genes is less in the bhlh mutants than that in the WT.Therefore,our results provide important insights into the molecular mechanism underlying the activation of direct targets by DYT1-b HLH089 heterodimers and demonstrate the protective roles of b HLH010/089/091 in maintaining fertility upon heat stress.
文摘Better understanding of electrochemical reaction behaviors of hydrazine electrooxidation at metal phosphides has long been desired and the optimization of reaction kinetics has been proved to be operable.Herein,the dehydrogenation kinetics of hydrazine electrooxidation at Ni_(2)P is adjusted by Co as the(Ni_(0.6)Co_(0.4))_(2)P catalyzes HzOR effectively with onset potential of–45 mV and only 113 mV is needed to drive the current density of 50 mA cm^(‒2),showing over 60 mV lower than Ni_(2)P and Co_(2)P.It also delivers the maximum power density of 263.0 mW cm^(-2) for direct hydrazine fuel cell.Detailed experimental results revealed that Co doping not only decreases the adsorption energy of N_(2)H_(4) on Ni sites,lowering the energy barrier for dehydrogenation,but also acts as the active sites in the optimal reaction coordination to boost the reaction kinetics.This work represents a breakthrough in improving the catalytic performance of non‐precious metal electrocatalysts for hydrazine electrooxidation and highlights an energy‐saving electrochemical hydrogen production method.
基金supported by the National Natural Science Foundation of China(Nos.U19A2017,21902047,51402100,21825201,21573066,and 21905088)the Provincial Natural Science Foundation of Hunan(Nos.2020JJ5044,2022JJ10006)。
文摘High entropy oxides(HEOs) have attracted extensive attention of researchers due to their remarkable properties. The electrocatalytic activity of electrocatalysts is closely related to the reactivity of their surface atoms which usually shows a positive correlation. Excellenet stability of HEOs leads to their surface atoms with relative poor reactivity, limiting the applications for electrocatalysis. Therefore, it is significant to activate surface atoms of HEOs. Constructing amorphous structure, introducing oxygen defects and leaching are very effective strategies to improve the reactivity of surface atoms. Herein, to remove chemical inert, low-crystallinity(Fe, Co, Ni, Mn, Zn)_(3)O_(4) (HEO-Origin) nanosheets with abundant oxygen vacancies was synthesized, showing an excellent catalytic activity with an overpotential of 265 mV at 10 mA/cm^(2), which outperforms as-synthesized HEO-500℃-air(335 mV). The excellent catalytic performance of HEO-Origin can be attributed to high activity surface atoms, the introduction of oxygen defects efficiently altered electron distribution on the surface of HEO-Origin. Apart from, HEO-Origin also exhibits an outstanding electrochemical stability for oxygen evolution reaction(OER).
基金the National Natural Science Foundation of China(31801568)the Natural Science Foundation of Tianjin City of China(18JCQNJC79300)+1 种基金the Science and Technology Major Special Projects and Engineering of Tianjin City(17ZXYENC00010)the Science and Technology Project of Gaoyou City,Jiangsu Province(GY201812)。
文摘Numerous polysaccharides isolated from plants have been used to augment traditional drugs in the treatment of cancer.In order to explore the influence to hepatocellular carcinoma,a novel cold water-soluble polysaccharide was separated from Rhodiola rosea L.root(RLP)and then its structure and anti-cancer activities were tested.The chemical compositions and high performance gel permeation chromatography(HPGPC)results indicated that RLP was an acid heteropolysaccharide with the molecular weight of about1.15×10~6 Da.Furthermore,ion chromatography(IC),Fourier transform infrared(FT-IR)and nuclear magnetic resoance(NMR)further indicated that RLP was main composed of→2,4)-α-Rha(1→,→5)-α-L-Araf-(1→,α-D-Glu,→6)-β-D-Galp-(1→,β-D-Man and→4)-α-GalpA-(1→.In vivo antitumor activities of RLP were carried out by using H22 tumor-bearing mice model.The results shown that RLP(100 and 300 mg/kg)could inhibit tumor growth of H22 cells from 23.59%to 45.52%and protect thymuses and spleen without damage.In addition,according to cell cycle,AV-FITC/PI and JC-1,RLP could induce dose-dependent apopto sis of H22 cells via S phase arrested which was through a mitochondrial related pathway.Our data indicated that RLP has a broader application prospect in anti-tumor preparations.
基金supported in part by the NSF of China(No.62171296)the Science and Technology Project of Beijing Municipal Education Commission(No.KM202010028005)。
文摘UAV-aided energy-harvesting WBANs where sensor nodes can harvest RF energy transmitted by a UAV have attracted considerable attention.However,how to maximize the sum-throughput of the sensor nodes with crosstier interferences from satellite and cellular systems has not been addressed.In order to bridge this gap,we devote this paper to developing two schemes with the fixed or variable duration of the energy-harvesting phase.Specifically,we formulate two non-convex optimization problems corresponding to the two schemes,and transform them to tractable subproblems,and accordingly two algorithms are proposed named HA-PC-TA and UAVPC-TA.In particular,we derive the closed-form optimum transmit power and time allocation for the sensor nodes and obtain the optimum UAV's hovering altitude in HA-PC-TA.We reveal the relationship between the optimum parameters and the allowed maximum transmit power of the VAU in UAVPC-TA.Finally,the simulations are conducted to validate the effectiveness of our proposed solutions.
基金funded by the National Science Fund for Distinguished Young Scholars with the project number 71904205the Chinese Academy of Medical Sciences(CAMS)Innovation Fund for Medical Sciences–A Strategic Study on Healthy China Development and Health system Reform(2021-I2M-1-046).
文摘Background:This study aimed to develop and validate test-based physical literacy scales(PLSs)for primary school students across different grades.Methods:Data were collected through a field survey conducted from June 1 to July 31,2022,involving 3,275 primary school students from four provinces in China.The questionnaires assessed four domains:physical knowledge,physical competence,physical motivation,and physical behavior.The Rasch model was employed for psychometric analysis.Results:The variance explained by measures for the PLSs was 53.1%,50.3%,and 54.7%,all exceeding the 50%threshold,confirming unidimensionality and robust internal consistency.This enabled effective differentiation among students with varying proficiency levels.The item-person map demonstrated optimal alignment between item difficulty and participant ability levels.Most items showed favorable fit statistics,with Infit mean square(MNSQ)and Outfit MNSQ values ranging between 0.5 and 1.5.Conclusions:The PLSs demonstrate validity and reliability in measuring physical literacy among Chinese primary school students across four components:physical knowledge,physical competence,physical motivation,and physical behavior.The scales measure a unidimensional construct,supporting the use of summed total scores for assessment.
基金National Key Research and Development Program of China(2022YFA1105100)National Natural Science Foundation of China(32301102+3 种基金32171323)Fundamental Research Funds for the Central Universities(YCJJ20230215)Science,Technology and Innovation Commission of Shenzhen Municipality(KCXFZ20211020164544008)Sanming Project of Medicine in Shenzhen(SZSM201812055).
文摘Current gold standard for the replacement of small-diameter blood vessel(ID<4 mm)is still to utilize the autologous vessels of patients due to the limitations of small-diameter vascular grafts(SDVG)on weak endothelialization,intimal hyperplasia and low patency.Herein,we create the SDVG with the tailored endothelialization by applying the engineered endothelial cell vesicles to camouflaging vascular grafts for the enhancement of vascular remodeling.The engineered endothelial cell vesicles were modified with azide groups(ECVs-N3)through metabolic glycoengineering to precisely link the vascular graft made of PCL-DBCO via click chemistry,and thus fabricating ECVG(ECVs-N3 modified SDVG),which assists inhibition of platelet adhesion and activation,promotion of ECs adhesion and enhancement of anti-inflammation.Furthermore,In vivo single-cell transcriptome analysis revealed that the proportion of ECs in the cell composition of ECVG surpassed that of PCL,and the tailored endothelialization enabled to convert endothelial cells(ECs)into some specific ECs clusters.One of the specific cluster,Endo_C5 cluster,was only detected in ECVG.Consequently,our study integrates the engineered membrane vesicles of ECVs-N3 from native ECs for tailored endothelialization on SDVG by circumventing the limitations of living cells,and paves a new way to construct the alternative endothelialization in vessel remodeling following injury.
基金supported by the National Natural Science Foundation of China(Grant No.52302007,52327801,51906086)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20210762).
文摘Spontaneous nucleation of SiC particles and giant macroscopic steps result in the surface roughness of the grown crystal for the top-seeded solution growth of SiC crystal.To suppress the surface roughness,the temperature gradient was carefully adjusted by changing the relative position of the crucible and induction coils.The numerical simulation and experimental results show that the surface morphology of the grown crystal becomes smoother and there are fewer spontaneous nucleation particles attached to the growth surface with the decrease in the relative crucible position,due to the increase of temperature at the entire solution surface and the reducing of temperature gradient near the growth surface.Accordingly,a lower temperature gradient,a larger solution velocity,a higher carbon concentration,and a smaller carbon supersaturation near the growth surface can be obtained when the relative position between the crucible and the induction coil is 70 mm,which is demonstrated to be the most favorable for the elimination of spontaneous nucleation of small SiC particles and suppressing surface roughening with the full width at half maximum(FWHM)of 37.5 arcsec of 4Hsingle bondSiC crystals.
